1. Field of the Invention
This invention relates, in general, to prefabricated door frames, and in particular to door frames constructed to minimize separation of joints.
2. Description of the Prior Art
The disadvantages of conventional construction of door assemblies on the construction site are well known. Skilled craftsmen are required and the construction is time consuming resulting in higher costs. To overcome these inherent disadvantages, the building industry has largely depended on prefabricated assemblies. Prefabricated assemblies of unitary construction have the disadvantages of fitting only one size of door frame opening and of being large and ungainly and therefor inefficient to ship. In attempting to overcome these problems, the art, more recently, has turned to knock down prefabricated door assemblies as typified by U.S. Pat. No. 3,338,008 issued to S. Sklar, U.S. Pat. No. 3,239,978 issued to J. H. Parker, and U.S. Pat. No. 3,250,049 also issued to S. Sklar. While solving the problems of shipping costs and door size, such assemblies heretofor, resulted in door assemblies which had a tendency to become loose at their connective joints and to become detached from the roughed in door frame.